1. Field of the Invention
The present invention relates to an electronic apparatus and a power circuit, and more particularly, to an electronic apparatus and a power circuit for improving a control voltage applied to an inverter unit.
2. Description of the Related Art
Referring to FIG. 1A, a conventional electronic apparatus includes a load 190, a power supply unit 170 for supplying a driving voltage to the load 190, an inverter unit 150 for controlling the level of the driving voltage applied to the load 190 by switching the driving voltage, and a control voltage supply unit 130 for outputting a control voltage to the inverter unit 150.
In the conventional electronic apparatus, the control voltage supply unit 130 includes a high-side control voltage output unit 133 and a low-side control voltage output unit 131, and the inverter unit 150 includes a high-side transistor Q11 and a low-side transistor Q12. Here, the high-side control voltage output unit 133 and the low-side control voltage output unit 131 apply a high signal and a low signal to the inverter unit 150 according to a predetermined control signal. The high-side and low-side transistors Q11 and Q12 of the inverter unit 150 are switched according to the high signal and the low signal output from the control voltage output units 131 and 133.
Here, voltages of the high and low signals output from the high-side control voltage output unit 133 are respectively V5 and V3, and voltages of the high and low signals output from the low-side control voltage output unit 131 are respectively Vcc and V1. A voltage applied to the emitter terminal of the high-side transistor Q11 is V3 and a voltage applied to the emitter terminal of the low-side transistor Q12 is V1. As such, if a control signal applied to the inverter unit 150 is “low”, voltages applied to the emitter terminals of the high-side and low-side transistors Q11 and Q12 are equal to voltages output from the control voltage output units 131 and 133 respectively.
In the conventional electronic apparatus, as the capacity of an inverter increases, the switching loss of the corresponding transistors gradually increases. Accordingly, it is required to reduce such switching loss.